The performance of non-volatile memory systems has improved over the past several years. Changes in technology management have pushed the non-volatile memory devices into cameras, computers, personal data assistants, smart phones, and proprietary business applications.
The current flash memory devices, based on charge storage technologies, have limited life spans due to damage of the charge storage layers during writes. The damage can be caused by physical weakening of the crystal structure used to store the charge. This condition is countered by limiting the number of writes and reads that an individual memory cell can undergo and balancing writes across all of the locations in the memory. The limited reliability of the cells has given rise to error correction strategies and distributed write operations in order to extend the useable life of the memory modules. Many maintenance processes can operate in background without the knowledge of the operator.
Other non-volatile memory technologies are in development that can increase the useable memory density while extending the lifetime reliability of the memory structures. These non-volatile memory technologies include spin transfer torque random access memory (STT-RAM), resistive random access memory, and programmable metallization memory.
Programmable metallization memories are also referred to as conductive bridge random access memory (CBRAM), each cell of which generally consists of an ionic source layer and an oxide film sandwiched between a bottom electrode and an upper electrode. Memory cell operation is due to formation/dissolution of a conductive bridge formed by electro-deposition of materials from the ionic source layer. In a current known fabrication method for CBRAM cells, layers are deposited by a physical vapor deposition (PVD) process. However, removal of sputter deposited materials from unwanted areas may leave residues which can damage cell performance. Further, PVD cannot be used in a damascene process to form confined memory cells.
Thus, a need still remains for a better conductive bridge memory system and method of manufacture thereof. In view of the push to ever-smaller devices and higher density memory, it is increasingly critical that answers be found to these problems. In view of the ever-increasing commercial competitive pressures, along with growing consumer expectations and the diminishing opportunities for meaningful product differentiation in the marketplace, it is critical that answers be found for these problems. Additionally, the need to reduce costs, improve efficiencies and performance, and meet competitive pressures adds an even greater urgency to the critical necessity for finding answers to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.